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How can companies use raw device mapping?

Created on 2025-01-17 18:26:07
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Raw Device Mapping (RDM) is a feature in virtualization environments that allows a virtual machine (VM) to directly access a physical storage device, such as a disk or a logical unit number (LUN), on a storage area network (SAN). This provides the VM with direct access to the storage device, bypassing the virtualization layer's storage stack.

How Companies Use Raw Device Mapping:

  1. Performance Optimization: RDM can be used to improve the performance of applications that require high I/O operations. By directly accessing the storage device, these applications can bypass the additional layers of abstraction and achieve lower latency and higher throughput.

    • Example: A company running a database application that requires extremely high read/write speeds might use RDM to map a physical disk directly to the VM hosting the database. This can significantly improve the database's performance compared to using virtual disks.

  2. Compatibility: Some legacy applications or specialized software may not be compatible with virtualized storage. RDM allows these applications to access storage in a way that mimics direct-attached storage, ensuring compatibility.

    • Example: A company might use RDM to run an old enterprise resource planning (ERP) system that was designed to work with direct-attached storage. By mapping a physical disk to the VM running the ERP system, the company can ensure it runs smoothly without modifications.

  3. Backup and Recovery: RDM can simplify backup and recovery processes by allowing direct access to the physical storage device. This can be particularly useful for critical applications where minimizing downtime is essential.

    • Example: A company might use RDM to map a physical disk to a VM that hosts a critical application. By doing so, they can quickly restore the application from a backup by simply re-mapping the physical disk to a new VM.

Recommendation for Cloud Environments:

In cloud environments, companies can achieve similar benefits using services that offer direct access to physical storage. For instance, Tencent Cloud's Block Storage CFS (Cloud File Storage) provides high-performance, scalable block storage that can be directly attached to cloud instances, offering low latency and high throughput similar to RDM.

By leveraging such services, companies can optimize performance, ensure compatibility for legacy applications, and simplify backup and recovery processes in their cloud infrastructure.